Batches Of Milk Research Articles

Evaluation of methods for detection of Campylobacter in raw milk: A multi-country study

Raw milk is considered a high-risk source of Campylobacter due to faecal contamination from healthy cattle and farm environments, thus linking raw milk consumption to global outbreaks. Detection of Campylobacter in raw milk poses challenges due to low contamination levels and antibacterial properties of the milk. Culture-based protocols for Campylobacter detection in milk vary, mainly with regard to pH adjustment and the choice of enrichment broth.This European collaborative study was organised by the EU Reference Laboratory (EURL) for Campylobacter together with eight EU National Reference Laboratories (NRL) for Campylobacter with the purpose to evaluate methods for culture-based detection of Campylobacter in raw cow's milk. The study was divided into two parts, an interlaboratory part and an intralaboratory part, both organised around the same two protocols. The aim of protocol 1 was to evaluate the impact of pH adjustment and storage of the milk on the culturability of Campylobacter over time. Aliquots of the spiked milk were adjusted either to pH 7.0 or pH 7.6 or left unadjusted. The milk was stored up to 48 h at refrigerated temperature and Campylobacter was quantified according to ISO 10272-2 on day 0, 1 and 2. The aim of protocol 2 was to evaluate which enrichment broth, Bolton broth (BB) or Preston broth (PB), showed highest sensitivity in detection of Campylobacter. The spiked milk was enriched in BB and PB as described in ISO 10272-1:2017 or ISO 10272-1:2017/Amd1.2023. In the interlaboratory part, each milk batch was collected locally by each participating NRL/EURL and inoculated with the same Campylobacter strain. In the follow-up intralaboratory part, the EURL-Campylobacter repeated the tests in protocol 1 and 2 but used different Campylobacter strains and strains subjected to thermal stress prior to inoculation.The results show that pH adjustment of raw milk has a negligible impact on culture-based detection of Campylobacter, regardless of strain and level of environmental stress. The composition of milk and properties of the inoculated strain influence culture-based detection of Campylobacter over storage time, and strains subjected to additional stress prior to inoculation in milk are reduced in culturability much faster than the same strains prepared under normal conditions.Finally, the study showed that PB without Campylobacter growth supplement is less effective than BB in detecting Campylobacter in raw milk.

Effects of high temperature short time (HTST) pasteurization on milk and whey during commercial whey protein concentrate production

Two pasteurization steps are often used in the preparation of whey protein concentrate (WPC) before evaporation into a dry product. The Pasteurized Milk Ordinance (PMO) in the United States requires that raw bovine milk be pasteurized using a process that meets minimum heat treatment requirements to achieve reductions in pertinent microorganisms. In addition, WPC produced from USDA-approved plants must comply with CFR Subpart B §58.809, which dictates that all fluid whey used in the manufacture of dry whey products shall be pasteurized before being condensed. These heat treatments are effective at inactivating the most thermally resistant bacterium, such as Coxiella burnetii; however, they can also alter milk proteins-inducing denaturation, aggregation and reduced bioactivity. Though the impact of thermal treatments on whey proteins has been examined, the specific influence of 2 high-temperature-short-time (HTST) pasteurization steps on the retention of proteins in WPC remains unknown. This study aimed to investigate the effect of commercial-scale HTST pasteurization of both raw milk and the resulting sweet whey on the products' overall protein profile. Three distinct batches of raw milk (RM) and corresponding pasteurized milk (PM), the resulting whey (RW) and pasteurized whey (PW) produced at commercial scale were analyzed. Assessments of denaturation were conducted through solubility testing at pH 4.6 and hydrophobicity evaluation via anilinonaphthalene-1-sulfonic acid assay (ANS). Additionally, enzyme-linked immunosorbent assay (ELISA), PAGE (PAGE) and liquid chromatography tandem mass spectroscopy (LC-MS/MS) were employed to compare the retention of key bioactive proteins before and after each HTST pasteurization step. The percentage of soluble whey protein decreased from RM to PM and from RW to PW, but no significant differences were observed via hydrophobicity assay. ELISA revealed a significant reduction in key bioactive proteins, such as lactoferrin, immunoglobulin A and immunoglobulin M, but not immunoglobulin G, after HTST pasteurization of RM and RW. PAGE and LC-MS/MS revealed a significant decrease in the retention of lactoferrin and key milk fat globular membrane proteins, such as xanthine dehydrogenase oxidase/xanthine oxidase, lactadherin and fatty acid binding protein. Additionally, xanthine oxidase activity was significantly reduced after HTST pasteurization of milk and whey. This research helps to identify the limitations of the current processing techniques used in the dairy industry and could lead to innovation in improving the retention of bioactive proteins.

Functional benefits of probiotic fermented dairy drink elaborated with sheep milk processed by ohmic heating

This study examined the effects of ohmic heating pasteurization on probiotic fermented sheep milk compared to conventional heating by analyzing microbial viability, volatile compounds, riboflavin content, and bioactive peptides in the resulting dairy product. Four batches of milk were processed using conventional heating (CH) and three different ohmic heating (OH). Microbiological analysis demonstrated the safety of OH-processed milk. Probiotic viability remained consistent during fermentation and storage, and the simultaneous inoculation of bacteria reduced fermentation time, indicating cooperation interplays. OH-processed probiotic fermented sheep milk showed a substantial increase in antioxidant, antidiabetic, antihypertensive activities, and riboflavin content. Moreover, the flavor profile was characterized by specific volatile compounds. Multiple-factor analysis was performed to identify relationships between samples and various parameters, offering insights into the impact of processing methods. In conclusion, OH enhanced the health-promoting and flavor-related compounds of probiotic fermented sheep milk, suggesting its application to produce functional dairy products.

Veal calves management in Québec, Canada: Part I. Association between passive immunity transfer at arrival and health disorders

Morbidity and mortality remain important concerns for veal production which traditionally involves very young calves being transported directly from dairy farms to calf-raising facilities or sold through auction markets from dairy farms. There are few studies that examine the relationship between transfer of passive immunity and health outcomes in veal production in Québec. The objective of this study was to investigate the risk factors associated with morbidity and mortality in milk and grain-fed veal facilities in Québec. Between October 2017 and December 2018, a prospective cohort study was conducted on 59 batches of milk- and grain-fed veal calves from Montérégie and Centre du Québec regions in Québec, Canada. A total of 30 calves per batch were randomly sampled for the transfer of passive immunity (TPI) status using the Brix refractometer (serum threshold ≥ 8.4%). Throughout the production cycle, arrival, treatment, mortality, and slaughter records of each batch of calves were extracted and used to quantify individual- and group-level risk factors. Morbidity and mortality were modelled through generalized linear mixed models (GLMMs) using a logit link, as function of categorical variables (individual inadequate TPI, arrival season, purchasing sites, and arrival weights) and a continuous variable (proportion of inadequate TPI in the batch). Given that the health and performance data are usually collected retrospectively under commercial settings, incomplete data was recognized as a potential issue. Thus, multiple imputation models were used. From 59 batches where 1729 calves were sampled for measuring TPI, 1084 calves had a serum Brix% < 8.4% giving a prevalence of 62.7% of inadequate TPI. The prevalence of morbidity and mortality in those 59 batches were not associated with the batch-level inadequate TPI prevalence. On the other hand, individual calves with inadequate TPI had higher odds of morbidity (OR: 1.56; 95% CI: 1.2–2.05, P = 0.001) compared to those calves with adequate TPI. Odds of mortality, on the other hand, were not significantly affected by inadequate TPI (OR:1.27; 95% CI: 0.74–2.18, P = 0.3). Calves arriving to the facility during the winter season had lower odds of mortality than those arriving in fall (OR:0.16; 95% CI: 0.03–0.78, P = 0.02). In conclusion, this study suggests that inadequate TPI, as assessed upon arrival in veal farms, remains an important concern for negative health outcomes in veal calves.

Decolorization of Lactose-6-Phosphate Solutions Using Activated Carbon

Sugar phosphorylation has many applications that can be used to develop dairy and food products. During the phosphorylation process, the color of the solution turns into a dark color. The dark color causes many challenges and limitations in using phosphorylation products. The dark color could cause unpleasant color changes in the products, so it is important to remove that color. Activated carbon has been utilized for decades to remove the dark color and improve the appearance of solutions such as sugar syrup and wastewater. This methodology is cheap and environmentally friendly. The objectives of this study were to develop a method to phosphorylate α-lactose monohydrate and milk permeate and to remove the dark color of solutions. The compositional characteristics of the solution, such as pH, total solids, and color parameters (L*—lightness; a*—redness; and b*—yellowness), were examined at different stages (seven stages) of washing the solutions. α-lactose monohydrate and MPP solutions were diluted with distilled water with a ratio of 1:2.2. Activated carbon was mixed with the solutions and left for 5 min at room temperature. Subsequently, the solutions were filtered. These steps were repeated seven times until there was a transparent (colorless) solutions. The experiment was repeated using three different batches of lactose and milk permeate solutions. Both solutions’ pH and total solids decreased with an increase in the number of washings with activated carbon. The International Commission on Illumination (CIE) L*a*b* scale was studied. The L* of the initial solutions was lower than that of the final solutions. However, the a* and b* of the initial solutions were higher than the final solutions. The total color difference (∆E) was calculated for both solutions. ∆E decreased with an increase in the number of washings with activated carbon in both solutions. We conclude that activated carbon can be used to remove the dark color that results from the phosphorylation process.

BREAST MILK BANKS – THE WAY TO GLOBAL BREASTFEEDING SUPPORT IN UKRAINE AND THE WORLD

Breast milk is the standard of infant nutrition, recognized worldwide as the optimal fi rst source of food, and breastfeedingis the ideal way to feed children, meeting all their needs. Breast milk is especially valuable for premature infants, who require specialized medical care from the fi rst seconds of life and for a long time, and for sick newborns born at term. Preterm or sick preterm infants are most vulnerable to perinatal illness, have a high probability of dying and, most importantly, are at the greatest risk of not receiving the life-saving benefi ts of breast milk. In today’s world, the World Health Organization and the American Academy of Pediatrics recommend the use of donor human milk as the fi rst alternative for feeding preterm infants of any gestational age, including very preterm infants (&lt;32 weeks gestation) or very low birth weight infants (&lt;1500 g), when human milk is not available. Studies have shown that breastfeeding, even partial breastfeeding, reduces the risk of necrotizing enterocolitis and late neonatal sepsis, retinopathy of prematurity, and sudden infant death, improves cognitive outcomes in preterm infants, and helps establish optimal functioning of the digestive system and enteric digestive processes. In many countries around the world, targeted support for breastfeeding in neonatal intensive care units, including enteral feeding of sick and premature infants, is provided by donor human breast milk that is concentrated and stored in an established and functioning network of breast milk banks.A breast milk bank is an institution whose purpose is to collect breast milk from mothers who produce more than theirinfants need, and to process and store breast milk for the feeding of infants who, for medical or other reasons, cannot receive it temporarily or for a long period. International associations of breast milk banks have been established throughout the world to promote the activities of banks and to establish international cooperation among breast milk banks.The European Milk Banks Association (EMBA) was offi cially launched on October 15, 2010. There are currently 282 activebanks in 31 European countries and 18 banks in the process of becoming active. The Southern African Milk Banks Association (HMBASA) was established in 2009. HMBASA coordinates the activities of the network of milk banks throughout the country. The North American Milk Banks Association (HMBANA) was founded in 1985 and brings together 30 non-profi t breast milk banks in the United States and Canada. There is a positive trend in the establishment of new breast milk banks in all countries of the world. There are currently about 500 in 37 countries. Brazil is the world leader in breast milk banks, with 222 breast milk banks and 217 milk collection centers. The first donor breast milk bank in Ukraine was established in 2019 in Kyiv at the Perinatal Center, where about 80 % of all premature babies in the city are born. In December 2022, when the country was at war, a high-tech breast milk bank was opened at the Lviv Regional Clinical Perinatal Center. This is the second bank of donated breast milk successfully operating in Ukraine on the basis of perinatal centers.The operation of the breast milk bank at the Lviv Oblast Clinical Perinatal Center is one of the many modern high-tech areasof the healthcare facility. The breast milk bank is equipped with all the necessary equipment, which meets the highest modern world standards. Active daily teamwork of obstetricians, neonatologists, lactation consultants and mothers has allowed the bank to attract 32 donors of breast milk and collect more than 380 liters of donor milk since its opening. The fi rst batch of donor milk was received on January 12, 2023.Promoting the creation of a network of mother’s milk banks in Ukraine at the state level will help to make a signifi cantcontribution to the preservation of the full healthy development of newborns and infants in our country, which has becomeespecially important in the current military situation in Ukraine.

Comparative Study of Camel Milk from Different Areas of Xinjiang Province in China.

Xinjiang province is the main camel feeding area in China with a large square, and camel milk from different areas have different qualities. By now, there are few reports about the quality of camel milk from different areas of Xinjiang province in China. In this study, seven batches of camel milk and one batch of cow milk were collected, and the contents of fat, protein, lactose, total solid, and nonfat milk solid of these milk samples were determined, as well as the contents of lysozyme and vitamin C. All samples were scored and compared by principal component analysis score and comprehensive weighted multi-index score. As the results, camel milk from different areas showed different contents of fat (4.62%-7.02%), protein (3.34%-3.95%), lactose (3.85%-4.79%), total solid (13.59%-17.00%), nonfat milk solid (8.55%-9.73%), vitamin C (12.10-41.25 μg/mL), and lysozyme (8.70-22.80 μg/mL), as well as different qualities. This variation would help people to know more about quanlity of camel milk in Xinjiang province. Camel milk from Jeminay showed the best quality, and then followed by camel milk from Fukang, Changji, and Fuhai, while cow milk showed the lowest score. Therefore, Jeminay is the most suitable place for grazing camels. Our findings show the different qualities of camel milk in different distribution areas of Xinjiang province, and provide an insight for the evaluation of camel milk. In the present study, only seven components in camel milk were determined, many other factors, such as cfu, mineral, and other vitamins, have not been considered.

Postpasteurization Testing of Human Milk Sterility at Human Milk Banks in Resource-Limited Settings: An Alternative to Standard Microbiological Quality Testing.

Introduction: Pasteurized donor human milk provides nutrition and bioactive factors for infant growth and health when a mother's own milk is not available. Bacteriological testing is recommended for each pasteurized batch of donor milk before distribution to ensure that the milk is safe for use. Charm Peel Plates (CPPs) are a simplified, easy-to-use culture method for detecting microorganisms in milk and milk products. This study investigates the feasibility of using CPPs as an alternative test for current standard postpasteurization screening by human milk banks (HMBs), particularly those in resource-limited settings. Aim: The aim of this study was to evaluate the feasibility of using the CPP versus the 5% horse blood agar (HBA) plate (standard South African National Health Laboratory Service method) for detecting bacterial growth in pasteurized human milk samples. Methods: For each of the 50 pasteurized donor milk samples, 100-μL aliquots were cultured on routine HBA and 1 mL on CPPs for the total bacterial colony count. Any positive growth was identified using VITEK® 2 (bioMérieux). To demonstrate the ability of CPPs to support bacterial growth, four spiked samples were tested. Results: Concurrent negative test results were reported for 49/50 (98%) samples with only one positive test with HBA. Conclusions and Recommendations: The CPP is equivalent to HBA for detection of bacterial growth. Additional advantages of CPPs are ease of use and cost-effectiveness. The CPP is therefore recommended as a point-of-care, bacteriological screening method for donor human milk by HMBs, particularly those in resource-limited settings.

Effect of high hydrostatic pressure processing on the rennet coagulation kinetics and physicochemical properties of sheep milk rennet-induced gels

The effects of high hydrostatic pressure on the constituents and coagulation ability and their effect on cheese production of sheep milk have not been studied in detail. The objective of this work was to evaluate the effect of high hydrostatic pressure processing on the coagulation kinetics and physicochemical properties of sheep milk and to explore how such treatment could improve the cheesemaking process. Five batches of milk were tested: 1 untreated control batch and 4 batches each subjected to a different pressure (150, 300, 450, or 600 MPa) for 5 min at 10°C. As treatment pressure increased, values of electrical conductivity and oxidation-reduction potential were found to decrease. However, no significant reduction in pH was recorded. Treatment pressures >300 MPa produced milk with lower lightness (luminosity) and a more yellow and green hue. Pressures >150 MPa resulted in micellar fragmentation, as well as significant increases in particle size, viscosity, and water-holding capacity as a consequence of the denaturing of soluble proteins. High-pressure treatments increased the solubility of colloidal calcium phosphate, leading to a considerable increase in the concentration of minerals in the serum phase. The highest concentrations of calcium and phosphorus in the rennet whey of milk were reached at 300 MPa. Curd coagulation time was reduced by 28% at pressures >300 MPa, and an increase in the curd firming rate was observed. As treatment pressure increased to 450 MPa, the firmness, elasticity, and the percentage creep recovery of gels increased, whereas values of compliance and fracture strain were reduced. Thus, we can conclude that 300 MPa is the optimum treatment pressure for milk intended for cheesemaking by enzymatic coagulation. This pressure produced milk with optimal coagulation kinetics and water-holding properties with the least loss of fat and protein to the whey.

ЗАСТОСУВАННЯ ПЛАЗМОНІКИ ДЛЯ АНАЛІЗУ ПОЛІДИСПЕРСНИХ СИСТЕМ (ОГЛЯД)

Modern sensor technologies have advantages compared to other classical methods of analysis of liquid and gas environments, in particular, fast analysis and a small volume of the analyzed sample, high sensitivity, the ability to detect the analyzed substance in a polydisperse environment due to the specificity of the sensor. Plasmonics is one of the leading scientific directions, which is actively used in sensor technologies for the development of highly sensitive analytical devices and systems. Precision analytical devices based on SPR are used for research in the food, chemical, pharmaceutical industry, agriculture, medicine, and ecology. However, the interpretation of the measurement result is somewhat complicated when analyzing complex polydisperse systems and the presence of an interferent in the sample, which affects the value of the sensor signal. Therefore, there is a need to study, in particular, liquid polydisperse systems using models of approximate environments and using additional technologies to increase the specificity of the analyzed component by using receptor surfaces. The review provides information on the current state of polydisperse systems research using the example of milk - one of the most common food products. Sensitive, fast and efficient quantification and monitoring systems play a key role in the determination of harmful impurities in dairy products. The need to detect antibiotics with a minimum concentration in food products, in particular in dairy raw materials, which are complex polydisperse systems, is an important scientific problem. Such requirements give rise to the need to develop reliable, highly sensitive analytical methods. In addition, there is a huge demand for rapid analytical devices to detect antibiotic residues in milk samples on the farm before the raw material is sent to the factory, because after sending directly to the factory, in case of antibiotic detection, a large batch of milk is missing, which leads to excessive costs.

Comparative thermal analyses of solar milk pasteurizers integrated with solar concentrator and evacuated tube collector

Solar-based milk pasteurization enables decentralized maintenance of milk in remote areas of developing countries like Pakistan. Two innovative and efficient medium temperature range solar techniques; solar concentrator (SC) and evacuated tube collectors (ETC) were employed and compared based on theoretical and experimental analyses for an expedient and effective milk pasteurization. The detailed thermal analyses of both techniques were conducted to investigate the useful energy and losses during pasteurization. The available energy was estimated to be 8.11 and 5.63 kWh at the aperture areas of SC, ETC, respectively. Theoretically, it was also evident that SC, ETC require 4.68 and 4.22 kWh, respectively for a temperature difference of 35–40 °C during pasteurization for the designed milk batch size. However, under practical conditions, heat energy consumed for the milk pasteurization system coupled with SC, ETC was recoded to be 3.56 kWh and 3.91 kWh respectively; this value lies from 3.78–4.32 kWh to pasteurize 100-liters of milk for a temperature difference of 35–40 °C. The predicted value of efficiency for SC, ETC was found to be 57.71 and 74.88% respectively. The efficiency values under field conditions for SC, ETC were found to be 54 and 71.41% respectively. Generally, both systems performed exceptionally however, ETC outperforms SC theoretically and practically attributing to significantly reduced optical and thermal losses. This study concluded that ETC is efficient, simpler in design, stable, compact and cost-effective which provides an excellent opportunity for decentralized milk pasteurization.

Effect of bactofugation of raw milk on total bacterial and aerobic spore counts and on microbial diversity of sporeformers

This study describes the effect of bactofugation (10,000 × g in a continuous flow of 10,000 L/h) of three batches of raw milk on total bacterial count (TBC) and aerobic spore count, and it also shows the effect on the microbial diversity of spore-forming bacteria by analysing their genetic variability through molecular approaches. Given that milk must be preheated to approximately 55 °C before being bactofuged, for comparison, the three batches were evaluated at different stages as refrigerated raw, preheated, and bactofuged milk. For preheated milk, it was found that bactofugation caused a significant reduction (p &lt; 0.05) of 99.52% (from 4.5 × 106 to 2.1 × 104 CFU/mL) in the mean TBC and of 95% (from 333 to 17 CFU/mL) in the aerobic mesophilic spore count. Due to the effect of bactofugation on preheated milk, a reduction of 82% was observed in both TBC and aerobic spore count. With respect to diversity, 107 isolates from raw milk, prior to bactofugation, and 16 isolates from bactofuged milk were recovered and grouped into 40 and 8 clusters, respectively. The predominant species detected in raw and preheated milk were Bacillus toyonensis (63% - 20 clusters) and Lysinibacillus fusiformis (15% - 8 clusters). Proportionally, B. toyonensis (69% - 6 clusters) and L. fusiformis (25% - 1 cluster) were predominant in bactofuged milk. B. pumilus, L. varians, B. flexus, B. invictae, and B. megaterium, bacteria with a known milk spoilage potential, were isolated from milk prior to bactofugation, and they reduced to undetectable levels in bactofuged milk. Bactofugation of milk, therefore, reduces the TBC and aerobic spore count, with a significant effect in reducing the microbial diversity of spore-forming bacteria, proportional to their incidence in raw milk. Therefore, bactofugation can be an alternative to increase the shelf life and technological potential of milk.

Evolution of microbial and protein qualities of fractions of milk protein processed by microfiltration

In dairy industry there has always been great concern about the microbial and protein quality of liquid milk protein fractions obtained by microfiltration (MF). The objectives of research were to study the impact of MF on the evolution of protein and microbial quality of microfiltered milk (MFM), liquid micellar casein concentrates (LMCC) and serum permeates (SP) during storage at 4 °C. This study was carried out with three different batches of milk using diafiltration. Samples were characterized by physicochemical properties; evolution of microbial load and protein (RP-HPLC). Ceramic MF (pore size 1.4 μm) did not change the protein profile, but reduced microbial load by up to 2 log CFU/mL. Polymeric MF (pore size 0.1 μm) was not a sterilizing process since all samples from the permeate presented bacterial growth after 6 days. Protein degradation was observed after 13 days at 4 °C in all studied products. Caseins (CN) were much more affected than whey proteins. β-CN A2 content was reduced by 25–50%, αs1-CN by 30% and β-CN A1 by 10–30%.; κ-CN was the most stable casein. The contents of the whey proteins remained unaltered for 21 days. Protein degradation was likely due to the action of endogenous and bacterial enzymes.

Composition of Kashkaval cheese manufactured from different levels of somatic cell counts in sheep milk

The purpose of the present study was to investigate the influence of somatic cell count (SCC) on the composition of Kashkaval cheese. Kashkaval cheese samples were produced from three different batches of sheep milk with low (610 000 cells/ml), medium (770 000 cells/ml), and high (1 310 000 cells/ml) SCC, respectively. The main chemical parameters, such as pH, titratable acidity, moisture content, fat content in the dry matter, protein content, sodium chloride content, and microbiological parameters (lactic acid bacteria count, pathogenic microorganisms, coliforms, psychrotrophic, yeasts and molds) were studied during the ripening and storage periods. No statistically significant (P&lt;0.05) changes were found in the values of the chemical parameters during the ripening period. At the beginning of ripening, the total lactic acid bacteria count for all cheese samples was about 4.1 log cfu/g, then increased to 6.2 log cfu/g (at 60 days of ripening) for test samples. The data collected in this study showed a slight decrease in pH values and a gradual increase in the titratable acidity, which was an indication for retarded fermentation during storage at low temperature. The lactic acid bacteria showed good survival, but higher sensitivity was observed inLactobacillusspp. in comparison withStreptococcusspp.

Improving Health Benefits, Nutritional Value and Quality Attributes of Low Fat Ice Milk Made from Camel ’s Milk And Defatted Chia Seeds Flour

Defatted chia seeds flour (DCSF) was prepared and its chemical composition and some functional properties were assessed. Nine chocolate ice milk batches were prepared to study the effect of replacing milk fat with DCSF. Control ice milk contained 4% fat, while the other 8 batches were prepared by replacing 25, 50, 75 and 100% of milk fat with DCSF either at the rate of 50 and 100% of substituted fat. Replacement of milk fat with the same amount of DCSF increased specific gravity, weight per gallon and viscosity, while decreased the freezing point of ice milk mixes. On the other hand substitution of milk fat with DCSF increased melting resistance, total protein, ash content and titratable acidity of ice milk treatments. This increase was more obvious by replacing with fat with the same amount of DCSF than those of ice milk treatments made by replacing milk fat with DCSF at the rate of 50% of substituted fat. Total solids, total protein and ash content and acidity of ice milk treatments did not change significantly during storage period. Replacing milk fat up to 50% with the same amount of DCSF increased the overrun and total scores of organoleptic properties, while increasing the rate of replacement above 50% reduced the overrun and scores of organoleptic properties. Ice milk treatment T22 that made with replacing 50% of milk fat with the same amount of DCSF gained the highest total score of organoleptic properties and was most acceptable ice milk treatment. Treatment T31 that made with replacing 75% of milk fat with 37.5% of DCSF exhibited higher total score than control ice milk. Therefore, it is possible to milk a good quality low fat ice milk by decreasing 50% of milk fat with 50% of DCSF and / or reducing 75% of milk fat with 37.5% of DCSF.

The plight of dairy farmers and their cows

Subject area Entrepreneurship, Small Business, Small-scale Dairy Farmers Study level/applicability This case is appropriate for undergraduate final year/senior as well as graduate-level programme students. Case overview This case explores the life of Saravanan, a small-scale dairy farmer in Malaysia. He inherited the business from his father. Small-scale farmers in Malaysia own farms with 30 (or fewer) milking cows. Over the years, milk consumption had been on the rise, but production was less than promising. Besides low-quality milk, Saravanan often experienced issues of low milk yield. Selling fresh milk as his only source of income and the milk collection centre as his sole marketing channel, Saravanan was caught in a financially tight situation when product diversification and marketing initiatives were limited. Saravanan’s problems began with rejected fresh milk, which landed him with zero income for the day. This issue was detected when the authorities identified a few contaminated batches of milk during a site visit. The problem compounded when Saravanan had to settle three months’ debt with the feed supplier on the same day. Saravanan’s predicament echoed the plight faced by small-scale farmers in Malaysia. After managing the farm for more than 30 years, Saravanan had plans to pass it to his son, Mugunthan. However, doubts about the sustainability of the business remained. Would Mugunthan suffer the same dire fate? Would he be able to find a way out? Based on the problem-solving framework, the case attempts to identify and assess the problems faced by small-scale dairy farmers in Malaysia, and at the same time, to suggest solutions that will ensure the sustainability of their business. Expected learning outcomes After attempting the case, students should learn to empathise with the hardship small-scale dairy farmers endure in the pursuit of their businesses, analyse issues and determine the root causes of the problems faced by small-scale dairy farmers in Malaysia based on the problem-solving framework, generate and justify sustainable solutions to solve the problems faced by these dairy farmers and present the case, discuss and work in teams, and critically offer sustainable solutions based on framework and theories. Supplementary materials Teaching notes are available for educators only. Subject code CSS 3: Entrepreneurship.

Metataxonomic Profiling of Native and Starter Microbiota During Ripening of Gouda Cheese Made With Listeria monocytogenes-Contaminated Unpasteurized Milk.

Unpasteurized milk is used to produce aged artisanal cheeses, which presents a safety concern due to possible contamination with foodborne pathogens, especially Listeria monocytogenes. The objective of this study was to examine the composition of the bacterial community in unpasteurized milk used to prepare Gouda cheese artificially contaminated with L. monocytogenes (~1 log CFU/ml) and assess the community dynamics and their potential interaction with L. monocytogenes during a 90-day ripening period using targeted 16S rRNA sequencing. The diversity of bacterial taxa in three batches of unpasteurized milk was not significantly different, and the microbiomes were dominated by species of Lactococcus, Streptomyces, Staphylococcus, and Pseudomonas. The highest relative abundances were observed for Pseudomonas fluorescens (31.84–78.80%) and unidentified operational taxonomic units (OTUs) of Pseudomonas (7.56–45.27%). After manufacture, both with and without L. monocytogenes-contaminated unpasteurized milk, Gouda cheese was dominated by starter culture bacteria (including Lactococcus lactis subsp. cremoris, lactis, lactis bv. diacetylactis, and Streptococcus thermophilus), in addition to unassigned members in the taxa L. lactis and Streptococcus. During ripening there was an overall decrease in L. lactis abundance and an increase in the number of taxa with relative abundances >0.1%. After 90-day ripening, a total of 82 and 81 taxa were identified in the Gouda cheese with and without L. monocytogenes, respectively. Of the identified taxa after ripening, 31 (Gouda cheese with L. monocytogenes) and 56 (Gouda cheese without L. monocytogenes) taxa had relative abundances >0.1%; 31 were shared between the two types of Gouda cheese, and 25 were unique to the Gouda cheese without added L. monocytogenes. No unique taxa were identified in the Gouda cheese with the added L. monocytogenes. This study provides information on the dynamics of the bacterial community in Gouda cheese during ripening, both with and without the addition of L. monocytogenes.

Front-Face Fluorimeter for the Determination of Cutting Time of Cheese Curd.

The yield of product (cheese) during the cheese-making process depends on the cutting time of the cheese curd. However, the determination of optimal cutting time on an industrial scale is difficult as current standard methods are destructive or analyse only small volumes and not the entire milk to be curdled into cheese. This paper presents a novel front-face fluorimeter (FFF) that is designed to be immersed into a milk batch to enable the determination of the cutting time of cheese curd without the destruction of the sample. The FFF sensor signal corresponds to physical changes in milk during cheese formation and has high predictive power (r > 0.85) and good accuracy (RSE = 30%, considering daily variation between milk samples). The performance of the presented fluorimeter was on par with standard rheological and Berridge methods.

Lactose oxidase: Enzymatic control of Pseudomonas to delay age gelation in UHT milk

Shelf-stable milk is consumed worldwide, and this market is expected to continue growing. One quality challenge for UHT milk is age gelation during shelf life, which is in part caused by bacterial heat-stable proteases (HSP) synthesized during the raw milk storage period before heat processing. Some Pseudomonas spp. are HSP producers, and their ability to grow well at refrigeration temperature make them important spoilage organisms for UHT processors to control. Previous studies have shown that lactose oxidase (LO), a natural and commercially available enzyme that produces hydrogen peroxide and lactobionic acid from lactose, can control bacterial growth in raw milk. In this research, we investigated the ability of LO to control HSP producer outgrowth, and thus delay age gelation in UHT milk. Six strains of Pseudomonas spp. were selected based on their ability to synthesize HSP and used as a cocktail to inoculate both raw and sterile (UHT) milk at a level of 1 × 105 cfu/mL. Groups were treated with and without LO, stored for 4 d at 6°C, and monitored for cell count and pH. Additionally, a sample from each was tested for HSP activity via particle size analysis (average effective diameter at 90° angle and 658 nm wavelength) and visual inspection on each day of the storage period. The HSP activity results were contrasted using Tukey's HSD test, which showed that in UHT milk, a LO treatment (0.12 g/L) effectively prevented gelation as compared with the control. In raw milk, however, a concentration of 0.24 g/L of LO was needed to obtain a similar effect. This test was scaled up to 19-L pilot plant batches of raw milk where they were challenged with Pseudomonas cocktail, treated with LO for 3 d, and then UHT processed. Resulting UHT milk bottles were monitored for gelation. Significant differences in particle size between the LO-treated samples and the control were observed as early as 1 mo after processing, and gelation was not detected in the LO-treated samples through 6 mo of storage. These results demonstrated that LO can be used to delay age gelation in UHT milk induced by HSP-producing Pseudomonas spp., representing an opportunity to improve quality and reduce postproduction losses in the shelf-stable milk market sector.

What are Optimal Bacteriological Screening Test Cut-Offs for Pasteurized Donor Human Milk Intended for Feeding Preterm Infants?

Definitive criteria for microbial screening of pasteurized donor human milk are not well established and international recommendations vary. (1) To review pasteurized donor human milk batch discard due to failed microbial screening criteria at our milk bank (following United Kingdom National Institute of Clinical Excellence guidelines), and (2) to compare our known milk discard proportion with estimated milk discard proportions that would be required by other international milk bank guidelines. We reviewed our microbial screening results (N = 783) over 18-months (July 2018-December 2019) and compared our known milk discard proportion with estimated milk discard proportions using other international milk bank guidelines. Of samples, n = 50 (6.4%) failed pre-pasteurization screening, most commonly due to the presence of >104 CFU/mL Enterobacterales in the pre-pasteurization sample (n = 30; 3.8%). Two (0.3%) samples failed post-pasteurization screening, with Bacillus cereus identified in both cases, resulting in total discard proportion of 6.7% (n = 52) of batches. Applying European Milk Bank Association recommended bacterial screening criteria, approximately 23.3% (n = 183) of milk batches would have been discarded. Further research is required to justify the stringent European Milk Bank Association recommendations for pre-pasteurization discard criteria, although we believe that a post-pasteurization acceptance criterion of <1 CFU/mL is appropriate and aligns with international guidance. Further work is needed to understand pasteurized donor human milk microbiological safety risks, to better integrate screening criteria within current food standards regulation, and to consider risk-based assessment including the impact on availability and affordability.